Pivoted lock for breech bolt locking members



4 Sheets-Sheet 1 INVENTOR BERN/7P0 flfl/AM/PD, m a Q ATTDRNE Y Feb. 6, 1951 B MAILLARD PIVOTED LOCK FOR BREECH BOLT LOCKING MEMBERS Filed Dec. 8, 1949 B. MAILLARD 7 2,540,684

. PIVOTED LOCK FOR BREECH BOLT LOCKING MEMBERS 4 Sheets-Sheet 2 JNVENTDR B7P/Vfl/?D MF/LLflFO,

BY Q ATT RNEY Feb. '6, 1951 Flled Dec 8 1949 Feb. 6, 1951 MAILLARD 2,540,684

PIVOTED LOCK FDR BREECH BOLT LOCKING MEMBERS Filed Dec. 8, 1949 4 Sheets-Sheet 3 A ORNE Y i atenteci cl). 6, 1-951 UNITED STATES PATENT 2,540,684 mvorrED 1.0mm; REE-6H V .LGCKING MEMBER'S Bernard Maillardg Geneva, Switzerland, assignor to Society 'Brevets Aero-Meca'niques;" S. A, Geneva, Switzerland, ;a society of Switzerland Annl'icationbeoemher 8, 194-9, shin ng-1,154 'Luxemburg D mber. 2 1, 48

The present invention relates to automatic firearms including a breech casing in which is slidably mounted amovable'breechblock which can be temporarily stopped in firing position by at least one retractable locking member carried by said breech casing. This locking member is shifted from active to neutral position under the action of a locking control system a portion of which is housed in the breech casing and the working of which is theoretically determined by the fining of a shot. =My invention is more pertieularly but not eiiolusivelyccncerned with firearms of this kind in which the locking control system is operated %by gas s t p d f barrel.

Its chief pu-rpose 1M0 provide firearms o'f this kind which are better adapted to meet the requirements of practice than those existing at-the present time and, in particular, such that there is }no :risk of the '"breechblock being untimely re: leased by an accidental *working of the locking control system. I Y

According to my invention, the firearm fbeing mounted slidable on a support with the interpo sition of a shock absorber system capable of "limiting recoil of said arm with respect to said support whena shotis fired, I provide along the path of zrecoil of the portion of the locking control system which is housed in the breech casing, a retractable abutment device which remains in,

active :position as long as the recoil -'of the armcompanying draw n s, given merely by was or example and in which:

Fig. 1 diagrammatically :shows, in axial 1011- gitudinal section ;and with parts cut away, an automatic firearm :acjcordingto my invention;

Fig. .2 issamerspective View of the breech mechanismiof this arm, centainparts having been removed and others .cut away so as better to illustrate the part function of the various elements; Fig. 3 is .an zlelevationa1 view not :a modification of the firearmeshownrby Figs. 1 and '12, this view showing ,onl-ya pontion of this firearm;

Fig. is vasplan view :corresponding to Fig. 3';

19 :Claims. (Cl. 89-490) 'Fig. =5 is a perspectivewiew, with parts cutaway}:

of an element of the structure of Figs. '3 and 4;

Fig. '6 "is an elevational view, in section on the line -V-I V-I of Fig. '8, of a portion of an automati-c firearmmade according to another niodification;

Fig. 7 is a horizontal sectional view on the line- Fig. 8 isa cross section on the line "VIIL-VIII' merits of the structure of Figs. 6 to Thefinearmas a whole, is of any suitable con struction, for instance as 'follows:

It includes -a barrel 1 at therear end of which is provided a breech casing 2 in which is slidahle,

in a direction parallel to the axis of said ba re-1',

a movable breechblock 3 subjected "to the action of a reouperator spring 4 which constaritly urges it in the iron'tward' direction.

Movable breecliblook a fitted with a bolt 5 adapted to bear, when said loreec'hblock reaches the and -of its frontw'arddisplacement, against an abutment key fi rigid with the breech casing 2,-the" contacting surfaces of said bolt a-nd said key 116- ing :so inclined that they give rise, when the shot is fired, :to a reaction which "tends to release the bo'lt.

Inorder .to prevent this i 'elease of bolt 5 from taking :place untimely, :I :provide' a locking eon trolgsystem operated :by gases tapped from he-r Such ;a control system may, for instance, 136'- made in the following conventional fashion:

.JI dispose; on either :side For movable breech-1 block 3, two sliding side pieces 1 connected to:

gather Joy :atransverse key i8 which carries the arm firi g pin-and extends zthnough an telongatecl slot -.0 m ovidedin the 'zmoyable lareechblock sand permits ,a complementary displacement :of :the' sliding pieces ,towa lgl 1 1 :iront after ithelhreechs block has reached its :j'ront ,nosition, 'i. e. the :end of its ,irontwandfitrqke, where it is to be locked. J

The under (edge of reach of these .sl-iding pieces 1 ,cooperates with=the top of belt-5 to :keepQi-t in active position has long assliding pieces 1 rema n in ,iro'nt position with .r es-pectto ibreechbl-ogk 3 'J (as shown by Fig. ,1), v151i11's. said ,under ed es or,

sliding pieces 1 are provided with notches la ar ranged, when sliding -pieces 1 have moved a ,predetermined distance toward the rear, 9 came; opposite t at which they release and enable :to 5 retract into breechblflqk releasi or neutral ,po

sition g v Sliding pieces! are given their recoil movement, by longitudinal push pieces 9 carried by breech casing 2 and actuated by a system including cylinder l andpiston II and mounted on the barrel I of the arm, this system being periodically supplied, owing to a port l2, with the combustion gases which fill the portion of said barrel at the rear of the projectile that is being driven off.

A firearm made as above described is mounted longitudinally slidable in a fixed support Sjwith the interposition of a shock absorbing system (not shown by the drawing) capable of limiting the recoil of the arm with respect to said support,

which support may be either pivotally mounted" or rigidly fixed to the framework of the device or machine which is equipped with the firearm.

Advantageously, I provide, slidable on breech casing 2, a loader carrying sliding member or part l3 made rigid with the arm support S, for instance by means of a key l3a. In operation, the firearm recoils with respect to its support and sliding member [3, rigid with said support, is thus given a relative longitudinal displacement with respect to the arm, which displacement is of the same amplitude, but in the opposed direction, as that of the arm with respect to its support (recoil). I

It' should now be noted that, with this construction, there might happen, in particular in the case of hang fire, an untimely and accidental release of the breechblock, which occurrence would have as its unavoidable consequence the partial or total destruction of essential parts of the arm if the shot now happened to be fired after said breechblock was accidentally released.

As a matter of fact, a certain rebounding of sliding pieces 1, after their full frontward movement is practically unavoidable, if of limited amplitude. Unfortunately, this rebounding risks, in certain conditions, of having an amplitude such that recesses Ia come opposite bolt 5, thus permitting retraction thereof into neutral position and, consequently, release of the breechblock.

'It will be readily understood that, if the shot is fired after this premature release (case of hang fire) the breechblock will be suddenly subjected to the maximum pressure of the gases and will be driven in the rearward direction with a force much higher than that ensuring. recoil of the breechblock during normal operation of the arm. The return system intended to brake the recoil stroke of said breechblock and to bring it back toward the front will be torn away, all the rear portion of the arm being thus more or less seriously deteriorated.

According to my invention, this drawback is obviated by providing-a safety device capable of limiting the rebounding of sliding pieces I to a permissible "amplitude (i.' e. one which does not permit release of the breechblock) as long as the recoil of the whole of the arm with respect to support S has not reached a value for which it is sure that the shot has been normally fired;

I preferably constitute this safety device in the form of a retractable abutment l4 carried by the breech casing 2 and adapted, in active position, to project across the path of recoil of sliding pieces I, so that rebounding of these pieces is limited to a permissible value. Return of said abutment l4 into neutral or retracted position is achieved, at the proper time, by a cam [5 carried by the loader carrying sliding part l3.

Advantageously the safety device is made according to the embodiment illustrated by the drawings:

Abutment I4 is given the shape of a fork the interval between the branches of which corresponds to the distance between sliding pieces 1.

I provide, inthe upper face of, breech casing 2, a recess or housing 2 a'in which said fork can fit, in its retracted pOsition; the transverse portion of fork l4 (i. e. the portion extending between its branches) rests upon the sharp edge 2b of recess 2a forming a pivot axis for said fork, whereby, when fork l4 pivots downwardly, under the action of return spring IS, the ends of" its branches come across the path of recoil of sliding pieces I. 7

Fork l4 includes anarm Ma the bevelled edge [4b of which is arranged to engage cam [5 when the amplitude of the recoil stroke of the firearm (i. e. of breech casing 2) with respect to support S reaches the predetermined minimum value for which the breechblock may be released without risk.

This automatic firearm works as followsr When firing takes place without incident, the, firing of a shot is immediately followed by a recoilof the firearm with respect to support S, which 1 recoil has for its effect, due to the cooperation of cam I5 (fixed on the loader carrying sliding part l3) with bevelled edge Mb carried by fork ll, of causing said fork to be retracted into its housing 2a and, therefore, of letting sliding pieces 1 free to recoil until they permit the breechblock to be released. On the contrary, ,when the return of the breechblock into closing position is not immediately followed by the firing of the shot (case of hang fire), the recoil of the arm is zero or anyway insufficient to bring bevelled edge 11 Mb into contact with cam I5 and fork M then remains in active position, that is to say in the position for which it permits only limited rebounding of sliding pieces I, but notbreechblock release.

Anyway, and whatever be the embodiment that is adopted, such an arm has the considerable kind.

It should now be noted that when the arm fitted with such a resetting, device, it will be necessary to arrange it so that its operation, and

even the mere fact of fitting it in position (if the device, in question is removable and fitted on the arm only at the time of a resetting operation) causes fork M to be retracted. intoits housing 2a and therefore permits release of the breechblock although the arm has not recoiled with respect to support S.

In order to illustrate this feature, the drawings show, by way of example, a pneumatic resetting device essentially constituted by a unit including a cylinder I 1' and a piston I8, this unit being mounted on one side of the breech casing 2, the piston N3 of said unit acting, during the recoil stroke, upona finger rigid with one of the sliding pieces I and serving. to drive said sliding pieces (for releasing the breechblock) then breechblock 3 toward the rear through the intermediary of i said sliding pieces.

With such a device, it is possible to obtain re traction of fork. I4 at the proper time, by disposing, across the path of travel-of piston ill, a

pushr-pieee Zlhwhich cooperates with the end 2|a at a lever 21 pivoted, by means oi an axis '22, to the loader carrying-sliding part i3, theother end 21b.- of said lever bearing upon thev end portion. M of fork l4 and causing said fork to "retract intoi-ts housing as soon as a resetting operation is started.

It. should be noted that it will be necessary to provide, bothfor the end 211a and for the end-Rib of lever '2 I, bearing surfaces of a substantial length so that said ends remain in contact, during firing, respectively with push piece and with. part Me, which participate in the arm recoil movement.

. Ithas been supposed, in the precedin descrip tion, thatv abutment member M is urged toward its; active position by spring I 6, or evenpessi-bly by the mere action of its own weight.

According to a modification, in order toimp'rove the safety of operation, abutment member I4 is imperatively brought into active position, when sliding pieces 1 are nearing the end of their frontward displacements, by the very movement of said pieces, which, reciprocally, cannot finish their frontward movement if, for any reason whatever, member ll. has not been brought into active position.

Suchan arrangement constitutes an important improvement because, as the system for-med by sliding pieces I generally carries the striking pm, percussion of the cartridge in the barrel is made impossible when abutment member has not been previously brought. into active position, since in this case sliding pieces cannot complete their frontward stroke. wherefore, when the-safety obtained by the bringing "of abutment member 14 into active position ceases to exist, for any reason whatever, the shot is not 'fired, so that any risk of accident is avoided.

=A construction corresponding to this principle rear face of which is bevelled in a frontward' and downward direction so as to cooperate with a similarly inclined cam surface "Pclca-rried bysliding piece 1' at the rear of its notch l'b.

Breech casing 2 is of course provided with receases for accommodating arm I' ic and lug Md. As for sliding piece I, it is provided with a groove 'lc to accommodate lug Md.

The operation of such a safety system is as follows: The breechblock being supposed to be held in rear position, when the sear is. retracted, saidbreechblock is driven tron'twardly by the action of its recuperator spring, lug Md travelling ingroove Tc. Sliding pieces I and .are also driven. frontwardly. When they are nearing the end of their frontward stroke, abutment member lllis pivoted, into active position by the-action of spring .16 and-also by that of cam surface I -d cooperating with therear bevelled face of lug. Md. If, ior any :reasonwhate'ver, member I i is pro-- vented from --pi-voting into active position, its lug Hitflops sliding. piece I (and thereiorera'lso 1) before: the-end of its .frontward stroke, so that the Cartridge is not fired.

According: to another embodiment. :of my'im vention, the abutment member, instead of being pivoted to the breech casing, is: pivotally carriedby the sliding piece with. which. it cooperates.

member; in the active position thereof, projects from the outline of the sliding piece so as to strike a corresponding projection of: the breech casing and therefore to limit thev amplitude of. the rearward displacements of said sliding piece. 0n the contrary, in neutral position, the abut menti member is retracted inside the outline of said sliding piece which can therefore :move freely towardthe rear with respect to t-he breech casing. A'dvantageously, there is one abutment member for each sliding piece.

Preferably; in this case also, when the sliding pieces are. nearing the end of their 'frontward stroke, the abutment members are im-p ra i y' brought into active position.

If A is the recoil stroke of the sliding pieces: with respect to the firearm-support S necessary to start the retracting of theabutment means;

If 'B is the recoil stroke of the sliding pieces with respect to the breech casing necessary to bring the abutmentmeans into contact with the breech casing; and

vIf C is the length of overlapping of thecooper ating means of the abutment member and of the arm supportfor keeping said abutment member in active position, then C must be smaller than or at most-equai-to B so that the abutment means can be retracted before, or just as, said means can strike "the breech-casing, and

A must :be greater-than B so that the abutment" means can, when necessary, strike the breech casing before their retracting movement is started. Actuallyh sho'uld' beequal to the sun-ref Aiand the limit amplitude of recoil of the sliding pieces just when a shot issbeing'fire'd An example of such an embodiment is illustrated by Figs. 6'to 9.

In this construction, each oi' the 'sl iding pieces- 'lcarries an abutment member l i-4 pivoted thereto about a transverse axis. These members are urged toward active position (as shown by Fig. 6) by springs H6.

The rear ends of the iabutment members active position are adapted to come into-contact witha surface I55] belonging to the. breech casing, to limit, in these conditions, the rearward movements of the sliding pieces.

Each of the abutment membersl -14 is provided at the rear part thereof, with lateral projections or lugs H lb adapted tocooperalteywhen'the slid ing pieces move rearwardly, with respect to the firearm support, with a. surface H5 rigid with 1 said support, so as to retract said abutment members H4, for normal operation.

At their front parts, abutment members H1 are provided with lugs l 1 40 adapted to cooperate,

when the sliding pieces are nearing the end o'f their frontward strokes, with inclined surfaces I5-|. carried by the firearm support, so as imperatively to bring members HA into active position. A groove it is provided, in the breech :casing, 1 for passage of lugs. H422 and H40.

Distances A, B and C, above referred toyare 1 shown on Fig. 6.

This construction 'works in the following man net: 7

Under-normal conditions of "operation, the =recoil of the'firearm with respect to its support is sufiicient to bring lugs H417 into contact with surfaces H5, which causes members H4 to be retracted and to permit further rearward movement of the sliding pieces.

When the sliding pieces are nearing the end of their frontward stroke, lugs. ll lc cooperate with fixed surface I5I to bring abutment members H4 into active position, in which they remain for a frontward displacement equal to C.

If, for some reason (for instance hang fire), the arm does not recoil sufficiently with respect to its support, abutment members H4 are not retracted before their rear edge comes against surface l50. Therefore, they prevent further rearward displacement of the sliding pieces, and the breech block cannot be released.

If, during the forward displacement of the sliding pieces, abutment members [l4 cannot bebrought into active position, surfaces l5! prevent the sliding pieces from finishing their frontward movement and the shot is not fired.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practi-- cal and efiicient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. In combination, a support, a firearm slidably mounted on said support for recoil with respect thereto and including a barrel, a breech casing at the rear end of said barrel, a breechblock slidable longitudinally in said breech casing, at least one looking member retractably carried by said breechblock to secure it to said breech casing in firing position, control means partly housed in said casing for temporarily holding said locking member in active position thereof, and retractable abutment means be-- ably, mounted on said support for recoil with respect thereto, said firearm including a barrel, a breech casing at the rear end of said barrel, a breechblock reciprocable longitudinally in said breech casing, at least one locking member retractably carried by said breechblock. to secure it to said breech casing in firing position, control means for temporarily holding said locking member in active position including at least one longitudinal sliding piece movable in said breech casing and mounted for limited longitudinal displacement with respect to said breechblock, said sliding piece being arranged to cooperate with said locking member to release it for shifting into retracted position in response to a given rearward displacement of said piece with respect to said breech casing, and means for moving said sliding piece rearwardly in response to the firing of a shot, an abutment member arranged to be interposed in active position between said sliding piece and said breech casing for limiting the rearward displacements of the first of said two last mentioned elements'with'respct to the other to values smaller than said given rearward-dis-i placement, said abutment member being retractable into one of said two elements to clear the other, means for urging said abutment member toward active position, and cam means carried by said firearm support for bringing said abutment member into retracted position in response to rearward displacements of said firearm with'respect to said support of an amplitude at least equal to a predetermined value.

'3; A combination according to claim 1 further comprising means operative by said controlmeans for positively bringing said abutment means into active position just after said lockingmember has been held in active position by said control means.

breech casing, at least one locking member retractably carried by said breechblock to secure it to said breech casing in firing position, control. means for temporarily holding said 7 locking member in active position including at least one longitudinal sliding piece movable in said breechcasing and mounted for limited longitudinal displacement with respect to said breechblock, said sliding piece being arranged to cooperate with said locking member to release it for shifting into retracted position in response to a given rear-3 ward displacement of said piece with respect to I ,said breech casing, and means for moving said.

sliding piece rearwardly in response to the firing of a shot, an abutment member arranged to be interposed in active position between said sliding piece and said breech casing for limiting the rearward displacements of the first of said two last mentioned elements with respect to the other to values smaller than said given rearward disa placement, said abutment member being retractable into one of said two elements to clear the other, means operative by said sliding piece -for positively bringing said abutment member into; active position at the end of the frontward movement of said sliding piece, and cam means carried by said firearm support for bringing said abutment member into retracted position in response to rearward displacements of said firearm with respect to said support of an amplitude at least equal to a predetermined value.

5. In combination, a support, a firearm slidably --mounted on said support for recoil with respect thereto, said firearm including a barrel, a breech casing at the rear end of said barrel, a breechblock reciprocable longitudinally in said breech casing, at least one locking member retractably carried by said breechblock to secure it to said. breech casing in firing position, control means for temporarily holding said locking member in active position including a sliding system constituted by two longitudinal sliding pieces movable in said breech casing on either side of said I breechblock nd mounted for limited longitudinal displacement with respect to said breechblock, said sliding system being arranged to cooperate with said locking member to release it for shift-1" ing into retracted position in response to a given rearward displacement of said system with respect to said breech casing, and means for mov-"" ing said sliding system rearwardly in response 3 to the firing of a shot, a fork-shaped abutment member having its branches at a distance from each other equal to the distance between said sliding pieces so that the ends of said branches cooperate with said sliding pieces, respectively, said fork-shaped member being arranged to be interposed in active position between said sliding system and said breech casing for limiting the rearward displacements of the first of said two I last mentioned elments with respect to the other to values smaller than said given rearward displacement, said fork-shaped member being retractable by pivoting about a transverse axis into one of said two elements to clear the other, means for urging said member toward active position and cam means carried by said firearm support for bringing said abutment member into retracted position in response to rearward displacements of said firearm with respect to said support of an amplitude at least equal to a predetermined value.

6. A combination according to claim 2 further including a, resetting device and means responsive to the operation of said device for bringing said abutment member into retracted position to permit release of the breechblock despite the fact that the firearm proper is not moved with respect to its support.

7 A combination according to claim 2 in which the means for moving the sliding piece rearwardly in response to the firing of a shotinclude at least one push-piece actuated by gases tapped from the firearm barrel.

8. In combination, a support, a, firearm slidably mounted on said support for recoil with respect thereto, said firearm including a barrel, a breech casing at the rear end of said barrel, a breechblock reciprocable longitudinally in said breech casing, at least one looking member retractably carried by said breechblock to secure it to said breech casing in firing position, control means for temporarily holding said locking member in active position including at least one longitudinal sliding piece movable in said breech casing and mounted for limited longitudinal displacement with respect to said breechblock, said sliding piece being arranged to cooperate with said looking member to release it for shifting into retracted position in response to a given rearward displacement of said piece with respect to said breech casing, and means for moving said sliding piece rearwardly in response to the firing of a shot, an abutment member arranged to be interposed in active position between said sliding piece 10 and said breech casing for limiting the rearward displacements of the first of said two last mentioned elements with respect to the other to values smaller than said given rearward displacement, said abutment member being retractable by pivoting about a transverse axis into said breech casing to clear the sliding piece, means for urging said member toward active position, and cam means carried by said firearm support for bringing said abutment member into retracted posi-- tion in response to rearward displacements of said firearm with respect to said support of an amplitude at least equal to a predetermined value. 9. In combination, a support, a firearm slidably, mounted on said support for recoil with respect thereto, said firearm including a barrel, a breech casing at the rear end of said barrel, a breechblock reciprocable longitudinally in said breech piece rearwardly in response to the firing of a.

shot, an abutment member arranged to be interposed in active position between said sliding piece and said breech casing for limiting the rearward displacements of the first of said two last mentioned elements with respect to the other to values smaller than said given rearward displacement, said abutment member being retractable by pivoting about a transverse axis into said sliding piece to clear said breech casing, means for urging said member toward active position, and cam means carried by said firearm support for bringing said abutment member into retracted position' in response to rearward displacements of said-firearm with respect to said support of an amplitude at least equal to a predetermined value.

BERNARD MAILLARD.

No references cited. 

